OZONE LAYER protects the earth from harmful ultraviolet radiations and therefore it is important to preserve it. 16th September is celebrated as the International Day for the Preservation of the Ozone Layer every year.

This event commemorates the date of the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987.

“The hole in the ozone layer is a kind of skywriting. At first it seemed to spell out our continuing complacency before a witchs brew of deadly perils. But perhaps it really tells of a newfound talent to work together to protect the global environment.” (Carl Sagan)


In 1987 representatives from 24 countries met in Montreal and announced to the world that it was time to stop destroying the ozone layer. In doing so, these countries committed themselves, via the Montreal Protocol on Substances that Deplete the Ozone Layer, to get the world rid of substances that threaten the ozone layer.

On December 19, 1994, the UN General Assembly proclaimed September 16 to be the International Day for the Preservation of the Ozone Layer, commemorating the date when the Montreal Protocol on Substances that Deplete the Ozone Layer was signed in 1987. The day was first celebrated on September 16, 1995.

What is ozone layer?

Ozone layer is a region of our atmosphere from 19 to 48 km above the surface of the earth that contains relatively high amount of ozone (O3). Its concentration in atmosphere is about 10 ppm.


Ozone is a molecule containing three oxygen atoms. It has strong odor and is blue in colour. Normal oxygen molecule has two oxygen atoms and is colourless and odorless. Atmospheric ozone is more concentrated in the stratosphere layer, which is about 15 to 30 kilometers above from the earth surface.

Out of each 10 million air molecules, about 2 million are normal oxygen, but only 3 are ozone. This shows that ozone is very much low in concentration than oxygen.

Origin of Ozone Layer:

British Physicist “SIDNEY CHAPMAN” in 1930 discovered the photochemical mechanisms that give rise to the ozone layer In Earths stratosphere, ozone is created by striking oxygen molecules (O2 ) and ultraviolet light, then the oxygen molecules are broken into the two oxygen atoms each called atomic oxygen, one atomic oxygen combines with the oxygen molecule and forms the ozone. Ozone is itself unstable and when ultraviolet light hits, it splits into the molecule of oxygen and one oxygen atom. This is a continuous process and cycle is called the Ozone – Oxygen Cycle.

Good and bad ozone for health and ecosystems:

Ozone can be good and bad as well for health and ecosystems. “GOOD” ozone is found in the earths stratosphere and protects the earth and ecosystems from harmful ultraviolet rays. “BAD” ozone is basically an air pollutant that damages the crops, trees and vegetation. It also affects the health of the human being.

Why is it important to save the ozone layer?

Ozone in the stratosphere (upper atmosphere) and in troposphere (lower atmosphere) is chemically identical. Both contain three oxygen atoms but have different effects and role in different atmospheres and living things etc.

Stratospheric ozone is sometimes referred as “good ozone” because it absorbs most of the biologically harmful ultraviolet rays and allows small amount of heat to reach the earth. The absorbance of the ultraviolet rays by ozone is the source of heat in the atmosphere.

Harmful effects of ultraviolet rays:

• More exposure to ultraviolet rays can lead to the eye problems, increasing the incidence of cataract, especially in the rural areas due to the absence of sufficient medical care

• It is considered as a main factor for the development of skin cancer.

• Severe exposure to UV rays can affect the immune system; it decreases the resistance to various diseases and reduces the effectiveness of vaccines.

Hence, we have to save the ozone layer to get rid of harmful effects of ultraviolet rays.

“The ozone layer provides important protection to all of us from the suns harmful rays. Its important that companies and individuals who work with ozone-depleting substances follow appropriate steps to ensure the materials are not released into the atmosphere. This helps keep the ozone layer intact.” (Robert Varney)

Allah almighty made our sky (ozone) a secure ceiling:

[021:032] “And (for you), we deemed the Sky to be safe and secure ceiling. Yet, these are the signs they overlook! “

[021:032] “And we rendered the sky a guarded ceiling. Yet, they are totally oblivious to all the portents therein.”

The “guards” in the sky is highly compatible with the ozone layer of the atmosphere. Because it is the protective layer in the sky, keeping harmful rays away from the Earth.

Which factors deplete the ozone layer?

The scientific evidence, accumulated over more than two decades of study by the international research community, has shown that human-produced chemicals are responsible for the observed depletions of the ozone layer. Such substances are called Ozone Depleting Substances.

There are many factors which are responsible for the depletion of ozone layer. Some of them are:

• The compounds containing the chemical elements fluorine, bromine, chlorine, carbon, hydrogen etc.

• The ozone depleting compounds containing chlorine, fluorine and carbon are called CFCs.

• CFCs are mainly used in coolants in refrigerators, freezers and air conditioners in buildings and cars manufacturing. Also found in industrial solvents, dry-cleaning agents and hospital sterilants.

• Ozone is depleted by the free radical catalyst as well like nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br)

• Carbon Tetrachloride is used in solvents and some fire extinguishers.

• Hydro fluorocarbons (HCFCs) are less harmful then CFCs but still cause ozone destruction and are potent greenhouse gases.

Measures to be taken for further prevention of ozone depletion:

Its very important to know that how can we prevent ozone layer, it can save our lives in many ways and will provide a clean atmosphere.

The important steps to be taken are:

• Your cars air-conditioner should have carefully serviced. Auto air-conditioners are the single largest source of CFC emissions in the US. Do not simply refill your leaky air-conditioner; if you dont have the leak fixed, the CFCs you leak will end up in the air. Go to a service station equipped to recycle the refrigerant otherwise, the CFCs will be vented into the atmosphere.

• Dont use foam plastic insulation in your home, unless it is made with ozone safe agents. Or use fiberglass, gypsum, fiberboard, or cellulose insulation instead of it.

• Dont buy a halon fire extinguisher for home use.

• Check labels on aerosol cans. VCR-head cleaners, boat horns, spray confetti, photo negative cleaners, and drain plungers are still allowed to contain CFC but such labeling isnt required.

• Choose an energy efficient model, when buying a refrigerator. Thus when the fridge wears out, less CFC will be released. All the refrigerators sold in the US contain CFC.

National Academy of Young Scientists (NAYS), Pakistan Science Foundation (PSF) and Emerging Nations Science Foundation are striving hard to increase the knowledge and awareness about the ozone and how can we prevent this precious ozone layer from getting destroyed. Now its your responsibility to spread the word and protect yourself by protecting the ozone layer.

“Reduce depletion of ozone; otherwise you will be in the Red zone.”

The writer is the second year student of MBBS at the Dow University of Health and Sciences (DUHS). She is working at a number of prestigious scientific and research institutes. She can be reached at<dr.mariamasif@gmail.com>